Early fluorocarbon carpet protectant treatments were typically formulated within cationic surfactant systems. With the advent of the use of anionic compositions to provide stain resistance in the cationic treatment, the problem of tip staining arose. When a carpet, pretreated with a stain resist, is treated with a cationic or cationically dispersed fluorochemical repellant, sometimes localized staining can occur on areas of the carpet fibers where the fluorochemical repellant has been deposited. In the industry, this is termed tip-staining. Tip staining is believed due to residues of cationic material on the carpet, the residues providing staining sites for acid dyes, such as caused by spills of soft drinks colored with the acid dye FD&C Red No. 40.
To address the tip staining problem anionic surfactant systems were developed and employed for carpet soil resists, but such surfactant systems compromised repellency. Kirchner in U.S. Pat. Nos. 5,414,111 and 5,565,564 has described certain polyfluorourethane compounds for providing oil and water repellent properties to a carpet substrate. When these polyfluorourethane compounds were applied to carpet substrates as aqueous dispersions using anionic surfactants, tip staining was not a problem. However, an ideal carpet protectant would exhibit higher levels of repellency, towards both oily and aqueous soils, than is provided by the existing art. With such higher levels of repellency, the soils fail to wet the fibers, and are thus readily removed.
Thus there is a need for carpet protectant formulations that improve repellency without either causing tip-staining or gelling problems, or detracting from the compatibility of anionic formulations. The present invention provides such formulations.